1. Field of the Invention
The present invention relates to a pen-based portable personal computer system and more particularly to a pen-based portable personal computer system which automatically goes into a low-power state after a predetermined period of inactivity in order to conserve battery power under the control of a keyboard controller. A main power switch is provided for initially powering up the system. On power up, a wake-up signal is generated just long enough to enable the keyboard controller to take control of the power management of the battery.
2. Description of the Prior Art
Portable personal computers are known to automatically go into a low power state after a predetermined period of inactivity. Even in the low power state, such portable personal computers place a significant drain on the battery power. As such, for extended periods of non-use, the main power switch is normally switched off to totally disconnect the battery power from the computer system. In order to awaken the portable personal computer from such a state, a main power switch must be switched on.
Some known portable personal computers are known to have a hibernate state during which there is a relatively insignificant drain on the battery. As such, these systems can be left in the hibernate state for relatively long periods of time without the need to use the main power switch. Such systems are known for notebook-type portable personal computer systems which utilize a mechanical switch that is interlocked with the cover such that anytime the cover is closed, the personal computer system will go into a hibernate state. In such systems, when the cover is placed in an open position, the switch is used to wake the portable computer system up and place it in a full-power state. While such systems obviate the need to switch the main power switch on and off, such systems do require a mechanical switch which not only adds to the cost of the portable personal computer system, but is subject to wear, and thus failure. In addition, some known portable personal computers do not utilize a cover and thus would not be able to utilize a mechanical switch in the same manner discussed above to place the computer system into a suspend state. Thus, the user is forced to utilize the main power switch, which can be cumbersome.